Low input torque rotor for vane pump
A vane-type fluid displacement unit having a housing, a drive shaft extending through the housing, a rotor secured to the drive shaft and disposed within the housing, the rotor having at least one non-smooth top or bottom surface, and at least one vane secured to the rotor.
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The present invention relates generally to fluid handling machines and, more particularly, to vane-type fluid displacement units having features of improved design.
Vane-type fluid displacement units are well known in the art. One such example of a typical vane pump is disclosed in U.S. Pat. No. 6,503,064 to Croke et al., which discloses a rotor having smooth top and bottom surfaces. Typically, the top and bottom surfaces of rotors are ground smooth to a surface finish of Ra 4-20 micro inches. Because of the ground surfaces of the rotor, fluid passing through the vane pump exerts a shear force on the rotor, thereby requiring greater input torque.
U.S. Pat. No. 5,560,741 to Edwards discloses a vane pump having a rotor with a trepanned or recessed portion centrally located on the top and bottom surfaces. The purpose of this recessed portion is to provide undervane fluid an escape path as the vanes move radially inward during rotation of the rotor and has no bearing upon the shear force exerted by the fluid on the rotor. Accordingly, there is a need in the art for an improved rotor that reduces the shear force exerted by the fluid on the top and bottom surfaces of the rotor.
It is therefore a principal object of the present invention to provide an improved vane-type displacement unit that operates with a minimum amount of input torque.
A further object of the present invention is to provide an improved rotor for a vane-type displacement unit that reduces the amount of shear force exerted by the fluid passing therethrough.
These and other objects will be apparent to those skilled in the art.
BRIEF SUMMARY OF THE INVENTIONThe present invention is directed toward a vane-type fluid displacement unit having a housing, a drive shaft extending through the housing, a rotor secured to the drive shaft and disposed within the housing, and at least one vane secured to the rotor.
The rotor has at least one non-smooth top or bottom surface. Specifically, in one embodiment, the top and bottom surfaces of the rotor are dimpled. Alternatively, the top and bottom surfaces of the rotor have slots, holes, pockets, or a shot peen pattern. As such, the non-smooth top and bottom surfaces introduce fluid turbulences across the rotor that reduce the shear force of the fluid against the rotor, thereby reducing the required input torque.
BRIEF DESCRIPTION OF THE DRAWINGS
As used herein, those skilled in the art will appreciate that a vane-type fluid displacement unit encompasses both vane-type pumps and motors.
With reference to
With reference to
At least one of the top or bottom surfaces 30 and 32 of the rotor 16 is non-smooth in order to introduce fluid turbulence across the rotor 16, thereby reducing the fluid shear force acting thereon. Preferably, both the top and bottom surfaces 30 and 32 are non-smooth. Specifically, as shown in
In operation, the vane-type displacement unit 10 operates with a minimum amount of input torque exerted on drive shaft 14 as a result of the improved rotor 16. Specifically, the non-smooth top and bottom surfaces 30 and 32 of the rotor 16, as shown in
The effect of the non-smooth top and bottom surfaces 30 and 32 on the input torque is substantial. The use of the dimples 36 shown in
It is therefore seen that through the use of an improved rotor with non-smooth top and bottom surfaces, the present invention reduces the amount of shear force exerted by the fluid, thereby permitting operation of a vane-type displacement unit with a minimum amount of input torque.
Claims
1. A vane-type fluid displacement unit comprising:
- a housing;
- a drive shaft extending through the housing;
- a rotor secured to the drive shaft and disposed within the housing, the rotor having at least one non-smooth top or bottom surface; and
- at least one vane secured to the rotor.
2. The device of claim 1 wherein the top and bottom surfaces of the rotor are dimpled.
3. The device of claim 1 wherein the top and bottom surfaces of the rotor have a plurality of slots.
4. The device of claim 1 wherein the top and bottom surfaces of the rotor have a plurality of holes extending therethrough.
5. The device of claim 1 wherein the top and bottom surfaces of the rotor have a plurality of pockets extending therethrough.
6. The device of claim 1 wherein the top and bottom surfaces have a shot peen pattern.
Type: Application
Filed: Sep 17, 2004
Publication Date: Apr 6, 2006
Patent Grant number: 7467935
Applicant: Sauer-Danfoss Inc. (Ames, IA)
Inventors: Michael Betz (Huxley, IA), Eric Bretey (Rowan, IA), Robert Klinkel (Ames, IA), Kevin Landhuis (Ankeny, IA)
Application Number: 10/944,031
International Classification: F04B 35/04 (20060101); F04B 17/00 (20060101);